Figure 3.
Dependence of the degree of coexistence on the relative initial amount of the C strain. With initial ratios of S : R : C = 1 : 1 : 1 (rS : rR : rC) in the cyclic scenario I, the R and C strain came to dominate the expanding front. As the initial ratio of the C strain rC was reduced, R strain sectors became broader, in agreement with experimental observations (depicted below the theoretical results; see also the electronic supplementary material, figure S5). Further reduction of the initial ratio of C weakened its allelopathic effect on S such that expanding S sectors emerged. A maximal number of coexisting strains along colony fronts was observed around S : R : C = 1 : 1 : 0.1 (24% of simulations exhibited three-strain coexistence; error bars: s.e.m., n = 250). The three-strain coexistence at this initial ratio was also observed in experiments. White scale bars represent 1 mm.